Q: Is 661,564 a Prime Number?
A: No, 661,564 is not a prime number.
A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 661564 can be evenly divided by 1 2 4 165,391 330,782 and 661,564, with no remainder.
Since 661,564 cannot be divided by just 1 and 661,564, it is not a prime number.